Just as an FYI Viking, if you want to use the L98 heads, you also need a Vette TPI base OR an '85-'86 F-body TPI base. The L98 heads use the early style intake bolt pattern which is different from your '89 heads.
Steve, I'm not trying to wreck your sale, just don't want to see someone go through the same headaches I've been through in the past with my TPI stuff.